UNIVERSITY  OF   CALIFORNIA  PUBLICATIONS 


COLLEGE  OE  AGRICULTURE 

AGRICULTURAL  EXPERIMENT  STATION 

BERKELEY,  CALIFORNIA 


SUDAN  GRASS 


BY 
B.  A.  MADSON  and  P.  B.  KENNEDY 


BULLETIN  No.  277 

March,  1917 


UNIVERSITY  OF  CALIFORNIA  PRESS 

BERKELEY 

1917 


Benjamin  Ide  Wheeler,  President  of  the  University. 

E  X  I '  E  R IMENT  STATION  ST  A  F  P 

IIKADS    OF    DIVISIONS 

Thomas  Forsyth  Hunt,  Director. 

Edward  J.  Wickson,  Horticulture   (Emeritus). 

Herbert  J.  Webber,  Director  Citrus    Experiment  Station;    riant  Breeding. 

Hubert  E.  Van  Norman,  Vice-Director;  Dairy  Management. 

William  A.   Setchell,  Botany. 

Myer  E.  Jaffa,  Nutrition. 

Eobert  H.  Loughridok,  Soil  Chemistry  and   Physics   (Emeritus). 

Charles  W.  Woodwortii,  Entomology. 

Ealpii  E.  Smith,  Plant  Pathology. 

J.  Eliot  Coit,  Citriculture. 

John  W.  Gilmore,  Agronomy. 

Charles  F.  Shaw,  Soil  Technology. 

John  W.  Gregg,  Landscape  Gardening  and  Floriculture. 

Frederic  T.  Bioletti,  Viticulture  and  Enology. 

Warren  T.  Clarke,  Agricultural  Extension. 

John  S.  Burd,  Agricultural  Chemistry. 

Charles  B.  Lipman,  Soil  Chemistry  and  Bacteriology. 

Clarence  M.  Haring,  Veterinary  Science  and  Bacteriology. 

Ernest  B.  Babcock,  Genetics. 

Gordon  H.  True,  Animal  Husbandry. 

James  T.  Barrett,  Plant  Pathology. 

Fritz  W.  Woll,  Animal  Nutrition. 
*A.  V.  Stubenrauch,  Pomology. 

Walter  Mulford,  Forestry. 

W.  P.  Kelley,  Agricultural  Chemistry. 

H.  J.  Quayle,  Entomology. 

Elwood  Mead,  Eural  Institutions. 

J.  B.  Davidson,  Agricultural  Engineering. 

H.  S.  Eeed,  Plant  Physiology. 

D.  T.  Mason,  Forestry. 

William  G.  Hummel,  Agricultural  Education. 

John  E.  Dougherty^  Poultry  Husbandry. 

S.  S.  Eogers,  Olericulture. 
fFRANK  Adams,  Irrigation  Investigations. 

H.  S.  Baird,  Dairy  Industry. 

David  N.  Morgan,  Assistant  to  the  Director. 

Mrs.  D.  L.  Bunnell,  Librarian. 

Division  of  Agronomy 

John  W.  Gilmore  B.  A.  Madson 

E.  L.  Adams  W.  E.  Packard 

P.  B.  Kennedy  Geo.  W.  Hendry 


*  Died  February  12,  1917. 

f  In  co-operation  with   office  of  Public  Eoads  and  Eural  Engineering,  U.   S. 
Department  of  Agriculture. 


SUDAN  GRASS- 
by  B.  A.  MADSON  and  P.  B.  KENNEDY 


CONTENTS 

PAGE 

Summary 196 

Introduction  196 

Adaptation  198 

Climatic   requirements   198 

Soil  requirements   - 200 

Drouth  resistance  200 

Sudan  grass  as  an  irrigated  crop 201 

Culture    202 

Preparation  of  the  seed  bed 202 

Seeding   Sudan   grass 203 

Time   of   seeding : 203 

Method   of   seeding 205 

Bate    of    seeding 208 

Cultivation 209 

Irrigation  210 

Sudan  grass  in  the  rotation 210 

The    hay    crop 211 

Time    of    cutting1 211 


i>-> 


Method    of    harvesting 211 

Yield   of   hay .' 212 

Feeding  value  of  Sudan  grass  hay 213 

Sudan    grass    pasture 215 

Seed   production 216 

Preparation  of  soil 218 

Time   of   seeding 218 

Method   of    seeding 219 

Bate    of    seeding 220 

Harvesting  the  seed  crop 220 

Threshing 220 

Cleaning   221 

Yield  of  seed 221 

Enemies 221 

Diseases    221 

Insects ■_ 222 

Weeds   222 

Distinction  between  Sudan  grass  and  Johnson  grass  seed 223 


*  The  Sudan  grass  experiments  were  carried  on  in   cooperation  with  the  office 
of  Forage  Crop  Investigations  of  the  United  States  Department  of  Agriculture. 


19G  UNIVERSITY  OF   CALIFORNIA EXPERIMENT  STATION 


SUMMARY 

1.  Sudan  grass  was  obtained  by  the  United  States  Department  of  Agriculture 

from  Sudan,  Egypt,  1909. 

2.  It  is  closely  related  to  the  cultivated  sorghums  and  like  them  is  an  annual. 

3.  In  general  appearance  it  resembles  Johnson  grass  but  lacks  entirely  the  under- 

ground rootstocks  that  make  Johnson  grass  a  pest. 

4.  Two  or  three  cuttings  of  hay  can  be  obtained  from  it  under  favorable  con- 

ditions. 

5.  The  yield  varies  from  one  to  eight  tons  of  cured  hay  per  acre,  dependent 

on  the  length  of  the  frostless  season,  the  temperature,  altitude,  soil  and 
amount  of  available  moisture,  either  by  natural  precipitation  or  by  irri- 
gation. 

6.  It  will  grow  in  a  wide  range  of  soils  from  sand  to  clay,  but  prefers  a  rich, 

well-drained,  sandy  loam. 

7.  The  seed  may  be  sown  broadcast,  drilled  or  in  cultivated  rows  after  all  danger 

from  frost  is  past,  and  the  soil  has  become  thoroughly  warm. 

8.  It  has  been  grown  to  a  greater  or  less  extent  in  almost  every  county  of  the 

state. 

9.  After  seeding  it  takes  from  75  to  80  days  to  secure  the  first  cutting,  about 

45  days  more  for  the  second  cutting,  and  50  days  more  for  the  third. 

10.  The  hay  is  palatable  to   all   classes   of   stock   as  it  is  sweet  like   the   sweet 

sorghums. 

11.  It  is  probably  as  nutritious  as  the  grass  and  cereal  hays,  but  cannot  compete 

with  alfalfa  in  this  respect. 

12.  A  seed  crop  can  be  produced  in  from  95  to  100  days  with  an  average  yield 

of  between  600  and  800  pounds  per  acre. 

13.  Sudan  grass  is  not  an  ideal  pasture  plant  as  in  light  soils  the  plants  are  apt 

to  be  pulled  while  being  grazed. 

14.  As  in  the  case  of  the  sorghums,  prussic  acid   (hydrocyanic  acid)   may  develop 

in  the  leaves  under  unfavorable  conditions  and  cause  stock  poisoning.  Up 
to  the  present  time,  however,  little  trouble  of  this  nature  has  been  reported, 
although  Sudan  grass  has  been  pastured  to  a  considerable  extent. 

15.  Sudan  grass  is  good  to  look  at,  easy  to  grow  and  handle,   grows  during  the 

summer,  gives  large  yields,  and  is  well  liked  by  stock. 


INTRODUCTION 

Sudan  grass  is  one  of  the  most  important  forage  crops  introduced 
into  the  United  States  in  the  last  twenty  years.  Its  introduction  dates 
back  to  1909,  when  C.  V.  Piper,  in  charge  of  forage  crop  investiga- 
tions for  the  United  States  Department  of  Agriculture,  secured  a 
half  pound  of  seed  from  R.  Hewison,  Director  of  Agriculture,  Khar- 
tum, Egypt.  It  is  cultivated  there  under  the  name  of  "garawi"  and 
is  probably  a  native  of  northern  Africa.  Piper  says  that  there  are 
strong  reasons  for  believing  this  plant  to  be  the  wild  original  form 
of  the  cultivated  sorghums  with  which   it  readily  crosses  wherever 


SUDAN  GRASS  197 

the  two  are  planted  near  each  other.  We  have  had  sent  to  us  a 
number  of  plants  secured  from  seed  of  Sudan  grass  grown  in  close 
proximity  to  shallu,  sometimes  known  as  Arabian  corn  or  Egyptian 
wheat,  one  of  the  sorghums.  The  plants  had  crossed  one  with  the 
other  so  that  nine  distinct  types  could  be  recognized.  In  general 
appearance  Sudan  grass  and  Johnson  grass  resemble  each  other  very 
closely,  but  the  former  is  an  annual  and  easily  eradicated,  while  the 
latter  is  a  perennial  with  underground  rootstocks  which  are  extremely 
difficult  to  kill  by  ordinary  cultivation.  Any  portion  of  these  root- 
stocks  when  separated  from  the  parent  plant,  even  if  only  an  inch  or 
so  in  length,  is  capable  of  producing  new  plants.  They  are  also  quite 
succulent  and  lose  their  moisture  very  slowly  so  that  it  is  difficult 
to  kill  them  even  by  exposure  to  drouth. 

The  leafage  of  Sudan  grass  and  Johnson  grass  looks  practically  the 
some.  Sudan  grass  in  poor  soil  with  insufficient  moisture  will  rarely 
exceed  three  feet  in  height,  while  under  ordinary  conditions  it  aver- 
ages five  feet,  or  with  very  favorable  conditions  as  high  as  ten  feet. 
When  sown  thickly  the  stems  are  usually  short  and  fine,  about  as  thick 
as  a  lead  pencil,  but  if  grown  in  rows  and  cultivated,  are  taller  with 
thicker  stems. 

The  flowering  parts  are  in  the  form  of  a  loose  panicle,  or  head,  at 
the  ends  of  the  stems  and  closely  resemble  Johnson  grass.  The  hulls 
are  awned  and  often  purplish  in  color.  Commercial  seed  rarely  has 
any  awns  as  they  are  broken  off  in  threshing.  As  many  as  one  hundred 
stems  may  be  produced  from  a  single  plant,  but  twenty-five  is  the 
usual  number.  The  stems  are  quite  leafy  and  remain  firmly  attached, 
both  good  points  in  a  hay  plant.  Although  the  stems  are  coarse,  this 
seems  to  be  no  objection  as  stock  eat  them  quite  readily. 

Sudan  grass  is  a  heavy  feeder,  as  would  be  expected  from  the 
large  tonnage  secured  in  a  season.  For  this  reason  it  would  not  be 
advisable  even  on  rich  soils  to  attempt  to  grow  it  on  the  same  soil 
in  two  succeeding  j^ears.  Unlike  legumes,  it  is  dependent  solely  on 
the  soil  for  its  source  of  nitrogen.  Wherever  possible  it  should  be 
rotated  with  a  leguminous  crop,  such  as  Canada  field  peas,  with  irri- 
gation in  the  counties  with  cold  winters ;  vetches,  lima  beans,  common 
beans  or  horse  beans  in  the  coastal  region  of  mild  winters,  and  cow- 
peas,  soy  beans  or  garbanzos,  as  a  summer  crop  in  the  southern  interior 
counties  where  irrigation  can  be  practiced. 

The  ideal  way  to  grow  Sudan  grass  would  be  with  a  legume  as  a 
mixture.  This  would  have  a  tendency  to  maintain  the  fertility  of 
the  soil  and  to  increase  the  protein  content  of  the  hay,  making  a  well- 
balanced  mixture  of  exceptional  feeding  value.     On  lands  not  subject 


198  UNIVERSITY  OF  CALIFORNIA EXPP]RIMENT  STATION 

to  irrigation  there  are  not  many  suitable  legumes  that  have  the  same 
drouth-resistant  qualities  to  enable  them  to  be  grown  as  summer 
crops.  The  two  most  likely  ones  are  the  chick  pea  or  garbanzo  (Cicer 
arietinum)  and  the  tepary  bean. 

With  irrigation,  cowpeas  or  soy  beans  have  been  grown  success- 
fully with  both  Sudan  grass  and  the  sorghums.  The  black-eye  bean, 
which  is  a  cowpca,  can  be  grown  in  many  of  the  warmer  coast  and 
interior  valleys  of  California  and  would  be  the  most  likely  to  succeed 
in  conjunction  with  Sudan  grass  as  a  mixture  under  irrigation. 

ADAPTATION 

Climatic  Requirements. — Sudan  grass  is  adapted  to  the  same  gen- 
eral climatic  conditions  as  the  other  members  of  the  sorghum  family. 
It  seems  to  prefer  a  warm  climate  of  relatively  low  humidity  and  like 
the  other  sorghums  it  is  very  susceptible  to  frost  so  that  its  growing 
season  is  limited  to  the  warmer  months  of  the  year.  From  observa- 
tions made  in  various  sections  of  the  state,  the  conditions  in  California 
as  a  whole  appear  to  be  favorable  to  its  growth.  Good  results  have 
been  obtained  with  the  crop,  not  only  in  the  large  interior  valleys,  but 
also  in  the  valleys  adjacent  to  the  coast  as  well  as  in  the  smaller  moun- 
tainous vallevs  located  at  elevations  of  from  three  thousand  to  four 
thousand  feet.  There  are  certain  locations  in  the  mountain  valleys 
that  are  not  subject  to  killing  frosts  owing  to  air  currents  which  cause 
atmospheric  drainage,  while  in  the  immediate  vicinitiy  lands  not  so 
situated  may  be  subject  to  frosts  every  month  during  the  spring  and 
summer.  This  accounts  for  the  apparent  contradiction  in  the  ability 
of  Sudan  grass  to  succeed  in  some  of  the  northern  counties.  In  some 
instances  good  crops  are  produced,  wrhile  in  others  it  is  a  complete 
failure.  Apparently,  however,  it  does  not  do  as  well  on  the  agricul- 
tural lands  subject  to  the  cold,  damp  ocean  breezes,  as  in  the  more 
protected  valleys  of  the  interior.  While  conclusive  information  is 
lacking,  it  is  just  probable,  judging  from  results  obtained  in  other 
states,  that  the  plant  is  but  poorly  adapted  to  altitudes  above  five 
thousand  feet. 

In  the  interior  valleys,  where  the  growing  season  is  from  six  to 
seven  months  in  length,  three  and  occasionally  four  cuttings  of  hay 
can  be  obtained.  The  first  cutting  requires  from  sixty  to  eighty  days 
to  mature,  depending  upon  the  season  and  soil  conditions  and  upon 
the  time  of  planting,  while  the  later  cuttings  reach  maturity  in  from 
forty-five  to  fifty-five  days. 

In  the  mountain  valleys  or  at  high  elevations,  the  growing  season 
is  usually  relatively  short  so  that  ordinarily  only  one  or  two  cuttings 


SUDAN  GRASS 


199 


Kn  «'  k&'i  ft 


sr! 


U   i 


hxmStif 


J 


Fig.  1. — A  single  plant  of  Sudan  grass  produces  many  stems. 

throughout  their  entire  length. 


They  are  leafy 


200  UNIVERSITY  OF  CALIFORNIA EXPERIMENT  STATION 

of  hay  will  be  obtained.  Obviously  the  total  yield  per  season  will  not 
be  as  large  as  in  the  more  favored  sections. 

Soil  Requirements. — From  the  general  observations  made  through- 
out the  state,  Sudan  grass  does  not  appear  to  be  at  all  exacting  in  its 
soil  requirements.  Favorable  results  have  been  obtained  with  the 
crop  in  many  sections  representing  a  variety  of  soil  types  and  con- 
ditions. Like  the  other  sorghums,  however,  it  does  best  on  a  rich,  well- 
drained  loam.  Exceedingly  heavy  soils  are  apt  to  be  cold  and  damp 
and  of  poor  physical  condition,  necessitating  somewhat  later  planting, 
and  in  many  cases  producing  a  rather  stunted  growth.  On  extremely 
sandy  soil,  the  growth  of  the  crop  is  usually  somewhat  lighter  than  on 
the  more  favorable  soil  types,  probably  due  to  low  fertility,  lack  of 
moisture,  or  poor  physical  condition.  On  most  soil  types,  however, 
the  growth  of  Sudan  grass  will  ordinarily  compare  quite  favorably 
with  that  of  almost  any  other  forage  crop  grown  under  similar  con- 
ditions. No  actual  tests  have  been  made  by  this  station  to  determine 
to  what  extent  Sudan  grass  will  succeed  on  soils  containing  alkali, 
nor  do  we  find  any  records  in  the  literature.  We  have  every  reason 
to  believe,  however,  that  as  in  the  case  of  the  sorghums  small  amounts 
of  white  alkali  will  not  be  injurious. 

Drouth  Resistance. — Perhaps  the  most  important  character  of 
Sudan  grass  and  the  one  which  will  be  of  greatest  value  in  stimulating 
the  use  of  the  crop  for  hay  purposes,  is  its  resistance  to  drouth.  This 
character  is  possessed  to  a  marked  degree  by  all  members  of  the 
sorghum  family,  but  is  probably  more  pronounced  in  the  Sudan 
grass  than  in  any  of  the  other  types.  This  was  strikingly  illustrated 
by  the  performance  of  the  crop  on  the  University  Farm  at  Davis  in 
1913,  which  was  an  exceedingly  dry  year,  the  total  precipitation 
amounting  to  only  8.84  inches.  The  grass  was  seeded  on  land  which 
had  been  cropped  to  cereals  the  previous  season  and  under  these  con- 
ditions produced  an  average  yield  of  3554  pounds  of  hay  to  the  acre. 
Regarding  the  ability  of  Sudan  grass  to  continue  growth  throughout 
the  drier  portions  of  the  season,  it  is  worthy  of  note  that  under  the 
conditions  mentioned,  the  average  yield  of  the  first  cutting  was  only 
937  pounds  of  hay  per  acre,  while  the  second  cutting  gave  an  average 
yield  of  1834  pounds  per  acre.  The  yield  of  the  third  cutting  was 
slightly  less  than  that  of  the  first.  Apparently  this  plant  has  a  re- 
markable ability  to  make  use  of  the  limited  soil  moisture  after  its 
shallow  but  extensive  root  system  has  become  fully  developed.  In 
all  probability  there  are  but  few  localities  in  the  state  where  the  rain- 
fall is  insufficient  to  produce  a  fair  growth.  Sudan  grass  is  in  fact 
one  of  the  few  plants  which  will  maintain  growth  throughout  the 


SUDAN  GRASS  201 

season  under  arid  conditions.  Obviously,  however,  the  yields  obtained 
will  normally  be  in  direct  ratio  to  the  moisture  available,  so  that, 
for  the  best  results,  rigid  conservation  of  the  moisture  supply  should 
be  practiced. 

The  most  critical  period  in  the  growth  of  the  Sudan  grass  seems 
to  be  while  the  plants  are  quite  small  or  during  the  seedling  stage. 
If  the  supply  of  water  at  the  time  of  seeding  is  insufficient  for  prompt 
germination,  or  for  the  maintenance  of  normal  growth  until  the  plants 
are  well  established,  permanent  injury  will  result.  This  was  clearly 
shown  by  the  failure  of  the  crop  on  the  unirrigated  Agronomy  experi- 
mental plots  in  1916.  In  the  absence  of  spring  rains  after  the  first 
of  March  the  soil  dried  out  rapidly  so  that  the  moisture  supply  to  a 
depth  of  six  to  eight  inches  was  inadequate  for  rapid  germination 
when  the  crop  was  seeded  in  April.  As  a  consequence  most  of  the 
seed  failed  to  germinate,  while  the  few  plants  which  did  appear  were 
weak  and  spindling  and  soon  perished.  On  a  few  spots  in  the  plots 
where  the  soil  had  retained  its  moisture  better,  a  fair  stand  was 
obtained,  and  the  growth  throughout  the  season  was  apparently 
normal.  This  would  seem  to  indicate  that  after  the  plants  have 
become  well  established  they  are  able  to  hold  their  own  under  trying 
conditions. 

Sudan  Grass  as  an  Irrigated  Crop. — To  what  extent  Sudan  grass 
may  become  of  importance  as  an  irrigated  crop  is  still  a  question,  as 
on  good,  well-drained  soils  it  must  compete  with  alfala.  While  yields 
may  be  obtained  which  will  compare  favorably  with  or  even  exceed 
those  of  alfalfa,  the  total  feed  value  per  unit  area  will  usually  be  con- 
siderably lower.  Furthermore,  because  of  the  beneficial  effect  of  the 
alfalfa  on  the  soil,  it  is  much  to  be  preferred  in  any  rotation  system. 
On  the  other  hand,  Sudan  grass  being  an  annual  may  often  be  em- 
ployed with  profit  as  an  emergency  forage  crop,  and  yet  not  interfere 
seriously  with  the  general  farming  scheme.  Alfalfa  is  more  of  a 
permanent  crop  requiring  at  least  a  year  to  reach  its  maximum  pro- 
ductivity and  is,  therefore,  not  so  applicable  to  the  short  rotation. 
Again,  when  the  supply  of  water  is  limited,  Sudan  grass  will  produce 
much  larger  yields  than  will  alfalfa  under  the  same  conditions. 

It  frequently  happens  that  alfalfa  yields,  due  to  over-pasturing 
or  the  encroachments  of  weeds,  or  other  causes,  have  become  too  low 
to  be  profitable.  In  the  preparation  of  the  land  for  reseeding  to 
alfalfa  no  better  crop  could  be  utilized  than  Sudan  grass,  as  there 
would  be  little  loss  in  tonnage,  the  land  would  be  benefited  by  the 
change  and  the  weeds  discouraged,  leaving  a  good  seed  bed  for  fall 
or  spring  seeding  of  alfalfa. 


202  UNIVERSITY  OF  CALIFORNIA EXPERIMENT  STATION 

There  are  large  areas  of  land  in  California  whieh  could  be  utilized 
for  alfalfa,  but  for  the  overflow  from  the  rivers  in  winter  and  early 
spring.  These  lands  are  sufficiently  drained  by  the  time  for  seeding 
Sudan  grass.    In  such  localities  large  crops  of  hay  can  be  produced. 

During  the  season  of  1913  and  1914,  Sudan  grass  was  grown  at 
the  University  Farm  both  with  and  without  irrigation.  In  1913  the 
unirrigated  plots  gave  an  average  yield  of  1.8  tons  of  hay  to  the  acre, 
while  the  irrigated  plot  yielded  3.9  tons  per  acre.  In  1914  the  aver- 
age yield  of  the  dry  plots  was  six  tons  per  acre,  and  of  the  irrigated 
plots  7.6  tons  per  acre.  In  neither  case  did  the  crop  obtain  the  opti- 
mum amounts  of  water  as  only  one  light  irrigation  per  cutting  was 
applied.  During  the  latter  season  the  average  yield  of  well  established 
alfalfa  was  seven  tons  per  acre,  though  this  crop  received  consider- 
ably more  water  than  did  the  Sudan  grass. 

CULTURE 

Preparation  of  the  Seed  Bed. — The  seeds  of  Sudan  grass  are  rather 
small  so  that  a  well-prepared  seed  bed  is  necessary  to  insure  prompt 
germination  and  a  good  stand.  In  most  sections  of  California  the 
best  results  will  probably  be  obtained  by  plowing  the  land  rather 
deep  in  the  fall  or  early  winter,  and  allowing  it  to  lie  in  the  rough 
state  throughout  the  rainy  season.  In  this  condition,  the  absorption 
of  the  winter  precipitation  will  be  greatly  facilitated,  at  the  same 
time  assuring  a  sufficient  packing  of  the  soil  for  a  good  seed  bed. 

If  the  field  is  reasonablv  free  from  weeds  the  seed  bed  mav  then 
be  prepared  with  a  disc  and  a  harrow.  If,  however,  the  weed  growth 
is  rather  heavy  a  shallow  plowing  early  in  the  spring  may  be  neces- 
sary before  a  good  seed  bed  can  be  secured. 

In  some  instances  spring  plowing  has  been  recommended  for  crops 
of  this  character  on  the  ground  that  the  spring-plowed  land  warmed 
up  somewhat  more  quickly,  making  earlier  seeding  possible.  While 
definite  information  along  this  line  is  wanting,  the  fact  that  the  soils 
in  this  state  are  subjected  to  rather  cold  rains  during  the  month  of 
March,  makes  this  effect  seem  rather  doubtful. 

When  the  land  has  been  plowed  in  the  spring,  as  may  sometimes 
be  necessary,  more  labor  is  usually  required  to  get  the  soil  worked 
down  into  a  good  seed  bed  than  when  the  land  has  been  fall-plowed, 
since  the  rain  falling  upon  the  land  at  this  season  of  the  year  is  seldom 
sufficient  to  pack  the  soil  properly.  The  bottom  of  the  seed  bed  must 
be  rather  firm  and  compact  in  order  to  establish  proper  capillary 
connection  with  the  soil  beneath,  as  well  as  to  provide  a  rather  firm 
base  on  which  to  plant  the  seed.    Only  the  surface  two  or  three  inches 


SUDAN  GRASS  203 

of  soil  should  be  loose  and  finely  pulverized,  which  is  sufficient  to 
check  evaporation  and  provide  the  necessary  aeration  for  the  germin- 
ation of  the  seed. 

Seeding  Sudan  Grass. — Sudan  grass  is  a  new  crop  in  this  country 
and  differs  materially  from  any  of  the  better  known  crops  in  its 
adaptation  and  manner  of  growth.  For  this  reason,  no  precedent  is 
available  to  guide  the  grower  as  to  the  most  efficient  means  of  handling 
the  crop  except  such  general  knowledge  as  might  apply  to  the  plant 
family  as  a  whole.  To  secure  definite  information  as  to  the  best  time, 
rate  and  method  of  seeding,  both  with  and  without  irrigation,  experi- 
ments were  undertaken  at  Davis  in  1913.     While  this  work  has  been 


-s*    '"*- 


Fig.  2. — Sudan  grass  grows  so  tall  and  thick  that  weeds  have  no  chance  to  grow. 

in  progress  but  three  years,  some  rather  striking  results  have  been 
obtained. 

Time  of  Seeding. — Inasmuch  as  Sudan  grass  is  a  warm-weather 
plant  it  should  not  be  seeded  until  all  danger  of  frost  is  past  or  until 
the  soil  has  become  thoroughly  warm.  If  the  seed  is  planted  in  soil 
that  is  too  cold  the  germination  is  apt  to  be  low,  resulting  in  a  poor 
stand.  Then,  too,  the  cold  soil  or  atmospheric  conditions  encountered 
by  too  early  seeding  may  materially  stunt  the  early  growth  of  the 
plants  from  which  they  will  be  rather  slow  to  recover.  The  best  time 
of  seeding,  however,  will  necessarily  vary  with  the  location  and  to 
some  extent  with  the  type  and  character  of  the  soil.  The  results  of 
tests  conducted  at  the  University  Farm  at  Davis  during  the  past 
three  seasons  to  determine  the  effect  of  time  of  seeding  Sudan  grass 
for  hay  production  are  given  in  Table  I. 


204 


UNIVERSITY   OF   CALIFORNIA EXPERIMENT  STATION 


TABLE  I 
Date  of  Seeding 

Yield    of   hay    per 
Dry 

_A 


acre,    pounds 


Irrigated 


Date 
seeded 


First 
cutting 


Mar.    20 2,485.2 

Apr.    15 6,114.9 

May      1 1,275.3 

May    15 2,861.2 

June     1 1,635.0 

Mar.    17 3,561.6 

Apr.      6 4,120.2 

Apr.    20 4,169.2 

May      3 6,556.3 

May    18 6,425.5 

June     1 4,332.7 

Mar.    17 

Apr.      6 

Apr.    17 

May      1 

May    15 


Second 
cutting 


2,844.9 
2,943.0 
3,646.0 

4,888.6 
2,011.0 

6,025.0 
4,594.3 
5,320.1 
5,559.0 
5,714.3 
4,839.6 


Third 
cutting 


Total 

for 

season 


First      Second      Third 
cutting    cutting    cutting 


1914 
1,733.1   7,063.2 
2,844.9  11,902.8 

4,921.3 

7,749.8 

3,646.0 

1915 
4,569.8  14,156.3 


2,560  4,848 

7,080  4,400 

2,440  5,300 

4,560  4,980 

2,900  3,900 


2,660 
3,440 


Total 

for 

season 


10,0(50 

14,920 
7,740 
9,540 
6,800 


4,095.7 
2,681.4 
1,765.8 


12,810.2 
12,170.7 
13,881.1 
12,139.8 


9,172.3 


1916 


540 
6,110 
5,290 
5,820 
4,170 


5,000 
6,480 
7,010 
5,910 
6,350 


6,950 


12,490 
12,590 
12,300 
11,730 
10,520 


On  the  whole,  the  highest  yields  were  obtained  from  the  April 
planting  regardless  of  whether  the  plot  was  dry  or  irrigated.  While 
in  1915  the  highest  yield  was  obtained  from  the  earliest  seeded  plot, 
attention  must  be  called  to  the  fact  that  the  season  was  quite  favor- 
able for  growth  during  the  latter  part  of  March  and  the  first  of  April, 
while  the  latter  part  of  April  to  the  middle  of  May  was  very  cold 
and  wet  and  on  the  whole  unfavorable  for  growth. 

Plantings  made  later  than  May  3  produced  only  two  full  cuttings 
of  hay  during  the  season  as  compared  with  three  cuttings  from  the 
earlier  seeded  plots.  While  some  growth  was  obtained  after  the  sec- 
ond cutting,  it  failed  to  make  enough  growth  for  a  hay  crop  before 
it  was  killed  by  the  early  fall  frosts. 

The  low  yield  for  1914  from  the  plot  seeded  June  1  is  due  primar- 
ily to  a  poor  stand.  In  1915  better  results  were  obtained  as  the  soil 
contained  more  moisture  at  that  date  than  the  preceding  year,  due 
to  the  late  spring  rains.  The  stand,  however,  was  not  as  good  as  that 
obtained  on  the  earlier  seedings.  On  the  irrigated  plot  planted  June 
1,  1914,  had  the  water  been  applied  before  seeding  instead  of  after 
the  plants  were  up,  the  stand  as  well  as  the  yield  would,  in  alj  prob- 


SUDAN  GRASS  205 

ability,  have  been  greatly  improved.  In  1916  the  soil  was  so  dry  the 
latter  part  of  March  that  the  stand  obtained,  even  on  the  early  seeded 
plot,  was  very  poor.  The  later  plantings  were  irrigated  immediately 
after  seeding  and  much  better  results  were  obtained. 

While  in  this  experiment  the  latest  seeding  was  made  June  1,  it 
has  been  observed  that  when  the  land  can  be  irrigated  before  seeding, 
good  crops  of  hay  may  be  obtained  in  some  localities  by  seeding  as  late 
as  the  first  of  August.  On  the  whole,  however,  where  the  land  can  not 
be  irrigated  and  when  the  maximum  yield  of  hay  is  desired,  it  is 
advisable  to  seed  as  early  as  soil  and  climatic  conditions  will  permit. 
By  seeding  comparatively  early,  the  root  systems  of  the  plants  become 
thoroughly  established  while  the  moisture  supply  is  still  abundant, 
thus  enabling  them  to  make  a  better  growth  throughout  the  drier 
portion  of  the  year. 

Method  of  Seeding. — For  hay  purposes  Sudan  grass  may  be  seeded 
either  in  cultivated  rows  or  in  close  drills.  The  latter  method  will 
probably  meet  with  the  greatest  favor,  especially  when  the  supply  of 
moisture  is  fairly  abundant,  as  practically  no  attention  is  necessary 
after  the  crop  has  been  seeded.  When  put  in  in  this  way  the  ordinary 
grain  drill  may  be  used  for  seeding  the  crop  as  almost  any  good 
implement  can  be  set  to  seed  as  low  as  twelve  to  fifteen  pounds  to 
the  acre. 

In  the  drier  sections  better  results  will  often  be  obtained  by  seed- 
ing in  cultivated  rows  eighteen  inches  or  more  apart.  This  method 
provides  the  individual  plants  with  a  greater  area  from  which  to 
receive  sufficient  moisture  to  enable  them  to  develop  normally,  and 
at  the  same  time  permits  of  the  necessary  cultivation  for  the  con- 
servation of  the  moisture.  A  considerable  saving  of  seed  is  also 
effected,  which  may  be  an  important  consideration  when  the  price 
of  the  seed  is  high. 

For  planting  the  crop  in  rows  the  ordinary  grain  drill  may  be 
used  by  stopping  up  enough  of  the  holes  to  give  the  proper  spacing. 
Fair  results  have  also  been  reported  by  using  a  corn  planter  provided 
with  special  plates  for  dropping  the  seed. 

Experiments  to  determine  the  effect  of  various  methods  of  seeding 
on  the  relative  yield  of  hay  have  been  conducted  on  the  University 
Farm  during  the  seasons  of  1913,  1914,  1915,  and  1916.  The  results 
obtained  are  given  in  Table  II. 

While  the  results  given  in  this  table  show  considerable  variation 
and  are  not  readily  comparable,  the  yield  on  the  dry  plots,  for  the 
past  two  seasons  at  least,  was  decidedly  in  favor  of  the  eighteen-inch 
rows.    In  1913,  which  was  an  exceedingly  dry  season,  the  difference  in 


206  UNIVERSITY  OF   CALIFORNIA EXPERIMENT  STATION 


• 

TABLE  II 

Method  of  Seeding 

Yield    of    hay    per 
Dry 

A 

acre,    pour 

ids 

Irrigated 

A 

Method 

for 
seeding 

r 

First 
cutting 

Second 
cutting 

Total 
Third                 for 
cutting            season 

r 

First 
cutting 

Second 
cutting 

Third 
cutting 

Total 

for 

season 

Drilled,  24  lbs. 

1913 

per    acre.... 

1,780 

2,320 

1,040          5,140* 

4,710 

2,380 

1,920 

9,010 

18 -inch    rows 

840 

2,000 

880          3,720 

4,040 

2,940 

1,600 

8,580 

44-inch    rows 

1,100 

1,840 

800          3,740 

1,460 

4,680 

880 

7,020 

*  Received 

a  partial 

irrigation  early  in  the  season  by  mistake. 

Drilled,  20  lbs. 

1914 

per    acre.... 

4,578.0 

3,213.6 

2,436.1     10,227.7 

7,520 

3,600 

3,740 

14,860 

18 -inch    rows 

7,390.2 

4,202.0 

2,812.2     14,404.4 

6,600 

6,600 

4,820 

18,020 

36-inch    rows 

4,490.2 

2,335.4 

2,926.6     10,709.2 

4,560 

6,240 

7,300 

18,100 

Drilled,  25  lbs. 

1915 

per    acre.... 
18-inch    rows 

3,016.6 
3,008.4 
2,321.7 

3,482.5 
3,964.9 
3,474.4 

1,986.5       8,485.6 
1,765.8       8,739.1 
1,888.4       7,684.5 

1916 

36-inch    rows 

Drilled,  20  lbs. 

per    acre.... 
18-inch    rows 

4,800 

8,210 

13  010 

5,060 

7,280 

12  340 

3 6 -inch    rows 

2,820 

6,460 

9.280 

yield  between  the  eighteen-inch  rows  and  the  forty-four-inch  rows  was 
very  slight.  This  would  seem  to  indicate  that  when  the  supply  of 
moisture  is  fairly  abundant  the  highest  production  could  be  obtained 
by  planting  in  rather  narrow  rows,  while  under  drier  conditions,  at 
least  equally  as  good  yields  would  be  obtained  from  the  wider  rows. 

On  the  irrigated  plots  it  is  of  interest  to  note  that  in  1913  and 
1916  the  yield  decreased  from  the  drill  plots  to  the  thirty-six  and 
forty-four-inch  row  plots,  while  in  1914,  both  the  row  plantings  de- 
cidedly outyielded  the  drill  plot.  During  this  latter  season,  however, 
the  difference  between  the  two  row-plantings  was  too  slight  to  be 
significant.  It  is  quite  probable  that  further  experience  will  show 
that  when  the  crop  can  be  properly  irrigated,  the  method  of  planting 
will  have  far  less  effect  upon  the  yield  than  when  it  is  grown  as  a 
dry  land  crop. 

It  has  been  stated  that  in  some  sections  the  hay  produced  from 
row  plantings  was  somewhat  coarser  in  quality  than  that  grown  in 
close  drills.  In  the  experiments  at  Davis,  the  difference  in  this  re- 
spect was  not  as  great  as  might  have  been  expected,  especially  where 
the  conditions  for  growth  on  the  close-drilled  plats  were  good.     In 


SUDAN  GRASS 


207 


Fig.  .3. — Under  irrigation  Sudan  grass  produces  a  rank  growth, 
proper  time  the  hay  is  tender  and  palatable. 


If  cut  at  the 


208 


UNIVERSITY  OF   CALIFORNIA EXPERIMENT  STATION 


all  cases,  however,  the  plants  stooled  much  more  in  the  rows  than 
in  the  close  drills. 

Rate  of  Seeding. — The  proper  rate  of  seeding  Sudan  grass  will 
doubtless  vary  somewhat  with  the  local  soil  and  climatic  conditions. 
It  does  not  appear,  however,  that  the  rate  of  seeding  bears  as  direct 
a  relation  to  the  moisture  supply  as  does  the  method  of  seeding.  Be- 
cause of  the  free  stooling  character  of  the  plant,  the  actual  yield  will 
be  less  affected  by  the  rate  of  seeding  than  with  most  other  annual 
crops.  However,  the  excessive  stooling  which  takes  place  when  the 
stand  is  thin,  may  lower  the  quality  of  the  hay  owing  to  the  wide 
range  in  time  of  maturity  of  the  various  parts  of  the  plant.  If  the 
crop  is  harvested  when  the  main  portion  of  the  plant  is  at  the  proper 
stage,  many  of  the  later  suckers  will  be  quite  immature,  while  if  har- 
vesting is  delayed  until  all  suckers  are  fully  headed,  the  central  stem 
will  become  coarse  and  less  palatable. 


TABLE  III 

Rate  of  Seeding 


Rate 

seeded 

per 

acre, 

pounds 


Dry 

K. 


Yield    of   hay    per    acre,    pounds 


Irrigated 


First 
cutting 


15  780 

20  630 

30  780 

40  650 

10  5,460.9 

15  6,180.3 

20  6,180.3 

25  5,657.1 

35  6,861.0 

10  4,251.0 

15  4,406.3 

20  4,240.9 

25  4,937.7 

35  4,136.5 

10  

15  

20  

25  

35  


Second 
cutting 


1,680 
1,530 
1,820 
1,650 

4,937.7 
4,643.4 
3,335.4 
3,417.1 
4,447.2 

6,360.1 
5,951.4 
5,215.6 
4,005.7 
4,316.4 


Third 
cutting 


Total 

for 

season 


1913 


660 
480 
720 
900 


3,160 
2,640 
3,320 
3,200 


1914 
3,580.6     13,979.2 


3,041.0 
2,828.5 
2,583.3 
2,926.6 


13,864.8 
12,344.2 
11,657.5 

14,240.8 


1915 

4,684.3     15,295.4 


4,177.4 
3,932.2 
1,847.6 


1,602.3 


14,535.1 
13,388.7 
10,791.0 

10,055.2 


1916 


15! 


First      Second     Third 
cutting    cutting    cutting 


2,870     3,110     1,040 
2,960     3,630     1,080 


5,640 
6,480 
6,680 
4,800 
7,320 


8,540 
6,100 
4,320 
4,560 
5,020 


5,000 
2,820 
2,960 
2,960 
4,160 


Total 

for 

season 


7,020 
7,670 


19,180 
15,400 
13,760 
12,320 
15,500 


7,770      .... 

5,140 

12,910 

5,820 

5,740      .... 

11,560 

6,570 

8,790      .... 

15,360 

5,380 

5,880      .... 

11,260 

4,340 

4,810      .... 

9,150 

SUDAN  GRASS  209 

Results  of  tests  conducted  at  Davis  during  the  seasons  of  1913- 

1916,  inclusive,  to  determine  the  effect  of  various  rates  of  seeding  on 

the  yield  of  hay  are  given  in  Table  III. 

The  results  for  the  four  years  taken  as  a  whole  are  quite  variable. 

In  1913,  the  highest  yield  was  obtained  by  seeding  thirty  pounds  per 
acre,  while  the  next  higher  yield  was  obtained  when  the  rate  of  seed- 
ing was  forty  pounds.  In  1914,  the  yield  decreased  with  an  increase 
in  the  rate  of  seeding  from  ten  to  twenty-five  pounds  per  acre  both 
under  dry  culture  and  with  irrigation.  On  the  dry  plats  the  thirty- 
five-pound  seeding  produced  the  highest  total  yield,  though  the  differ- 
ence between  the  yield  on  this  plat  and  the  one  seeded  at  the  rate  of 
ten  pounds  per  acre  was  not  sufficient  to  warrant  the  use  of  the  larger 
amount  of  seed.  In  1915,  the  total  yield  decreased  very  rapidly  with 
an  increase  in  the  rate  of  seeding.  In  1916,  on  the  other  hand,  seeding 
at  the  rate  of  twenty  pounds  per  acre  gave  the  best  results,  with  the 
ten-pound  seeding  second.  In  the  remaining  cases  the  yield  decreased 
with  an  increase  in  the  amount  of  seed  used.  Apparently  the  most 
productive  seeding  rate  where  the  crop  is  seeded  in  close  drills  and 
the  conditions  for  growth  are  good  is  from  ten  to  fifteen  pounds  per 
acre. 

Cultivation. — When  Sudan  grass  has  been  seeded  in  close  drills, 
cultivation  will  seldom  be  necessary  after  the  crop  has  been  seeded, 
though  if  the  soil  becomes  encrusted  before  the  plants  appear,  or 
while  they  are  still  quite  young,  a  light  harrowing  may  be  desirable. 
On  the  other  hand,  when  the  crop  is  seeded  in  rows,  some  cultivation 
will  be  necessary,  primarily  to  maintain  the  surface  mulch  and  check 
evaporation.  Weed  growth  will  seldom  be  a  serious  menace  to  Sudan 
grass,  as  the  crop  grows  with  such  rapidity  and  vigor  as  to  keep  the 
weeds  in  check  quite  efficiently.  It  is  only  when  seeded  extremely 
early,  in  which  case  the  growth  is  apt  to  be  rather  slow,  or  when 
seeded  on  very  foul  soil,  that  the  weed  growth  will  be  likely  to  be 
injurious. 

Two  cultivations  during  the  growth  of  the  first  crop  and  one 
cultivation  after  each  cutting,  or  after  each  irrigation,  will  usually 
be  sufficient.  The  first  cultivation  should  be  rather  deep  and  should 
be  given  as  soon  as  the  plants  are  large  enough  so  that  the  rows  can 
be  followed  easily.  Later  cultivation  should  be  more  shallow  in  order 
not  to  injure  the  surface  roots  of  the  plants. 

The  most  effective  implement  to  use  will  depend  somewhat  upon 
the  distance  between  the  rows.  When  the  rows  are  twenty-four  inches 
or  more  apart,  the  ordinary  two-horse  corn  cultivator  may  be  used, 
though  an  implement  with  rather  small  shovels  is  to  be  preferred  as 


210  UNIVERSITY  OF  CALIFORNIA EXPERIMENT  STATION 

the  small  shovels  have  a  greater  pulverizing  effect  on  the  soil  and 
leave  a  smooth  surface.  "When  the  rows  are  less  than  twenty-four 
inches  apart  a  one-horse  cultivator  of  the  type  used  for  cultivating 
truck  crops  will  probably  be  the  most  efficient. 

Irrigation. — While  Sudan  grass  will  doubtless  be  used  most  ex- 
tensively as  a  dry  land  crop,  there  is  no  question  but  that  as  a  forage 
crop  it  will  be  employed  to  some  extent  under  irrigation,  either  as  a 
supplement  to  alfalfa  hay  or  as  a  second  crop  to  follow  a  spring-grown 
crop.  Again,  in  sections  where  the  precipitation  is  low  and  the  supply 
of  irrigation  water  is  limited,  much  larger  yields  of  forage  will  often 
be  obtained  by  applying  the  small  amount  of  water  available  to  Sudan 
grass  rather  than  to  alfalfa.  While  no  definite  data  are  available  on 
the  amount  of  water  necessary  for  a  maximum  crop,  the  best  results 
will  probably  not  be  obtained  with  less  than  twenty-five  inches,  in- 
cluding the  natural  precipitation. 

When  Sudan  grass  is  planted  early  in  the  spring,  it  will  seldom 
be  necessary  to  irrigate  the  ground  before  seeding,  as  the  natural 
moisture  will  usually  be  sufficient  to  germinate  the  seed  and  start  the 
plants.  Ordinarily  three  or  four  irrigations  throughout  the  growing 
season  will  be  sufficient  under  most  conditions.  The  first  irrigation 
should  be  applied  when  the  first  growth  is  from  eighteen  to  twenty-five 
inches  in  height  or  just  before  heading.  The  later  irrigations  may  be 
applied  after  each  cutting  or  as  soon  as  the  new  growth  has  started. 
On  light  soil  it  will  doubtless  be  better  to  give  two  light  applications 
of  water  per  cutting  than  one  heavy  application. 

When  Sudan  grass  is  to  be  grown  following  a  spring  crop,  such 
as  grain,  irrigation  of  the  field  will  be  necessary  before  the  seed  bed 
for  the  grass  can  be  prepared.  If  a  rather  heavy  application  of 
water  is  given  at  this  time,  further  irrigations  will  not  be  necessary 
until  the  first  cutting  is  nearly  mature.  The  flooding  method  of  irri- 
gation is  to  be  preferred  with  Sudan  grass  even  when  seeded  in  rows, 
as  furrowing  between  the  rows  might  severely  injure  the  extensive 
surface  root  system  of  the  plants.  With  proper  checking  and  leveling 
of  the  field  before  seeding  no  great  difficulty  should  be  experienced  in 
securing  a  uniform  distribution  of  the  water. 

SUDAN  GEASS  IN  THE  EOTATION 
Inasmuch  as  Sudan  grass  is  an  annual  crop,  it  can  be  worked  into 
almost  any  rotation  in  much  the  same  manner  as  sorghums,  corn  or 
other  annuals  of  that  character.  Under  dry  farming  it  can  be  em- 
ployed in  the  cereal  rotation  with  profit  to  replace  grain  hay,  since 
it  is  more  drouth-resistant  and  much  more  productive  as  a  hay  crop 


SUDAN  GRASS  211 

than  any  of  the  cereals.  Being  a  sorghum,  however,  and  a  rank 
grower,  it  draws  heavily  upon  the  moisture  and  fertility  of  the  soil 
and  leaves  but  little  in  the  soil  for  improvement  except  the  decayed 
roots.  It  is  quite  probable  that  crops  susceptible  to  effects  of  plants 
of  this  character,  such  as  barley,  should  not  be  put  upon  the  land 
immediately  following  Sudan  grass. 

It  is  also  apparent  that  the  best  results  will  not  be  obtained  with 
Sudan  grass  if  it  is  put  upon  land  used  for  Sudan  grass  the  pre- 
vious season.  In  1915,  the  yield  obtained  on  land  which  had  been 
cropped  to  Sudan  grass  the  previous  season  was  only  4.24  tons  of 
hay  per  acre,  whereas  the  yield  on  land  upon  which  a  cultivated  crop 
had  been  grown  the  previous  season  yielded  6.69  tons  per  acre.  Both 
plots  were  seeded  at  the  same  time  and  at  the  same  rate,  and  other- 
wise handled  in  identically  the  same  manner.  The  fact  that  the  crop 
can  be  seeded  late  and  still  produce  large  yields  of  forage  will  doubt- 
less render  it  of  great  value  as  a  second  crop  under  irrigation.  It 
can  be  employed  in  this  way  to  follow  a  spring  crop,  such  as  grain 
or  spring  pasture  or,  in  fact,  any  crop  which  could  be  removed  from 
the  land  by  the  first  to  the  middle  of  July. 

THE  HAY  CEOP 

Time  of  Cutting. — In  order  to  secure  the  highest  quality  of  hay, 
Sudan  grass  should  be  cut  when  in  full  bloom.  If  harvesting  is 
delayed  until  the  seed  is  ripe,  the  hay  will  be  a  little  coarse  and 
a  little  less  palatable  than  if  cut  earlier.  The  decrease  in  feeding 
value  on  maturity  is  probably  not  as  great  in  Sudan  grass  as  with 
some  other  crops,  since  in  common  with  many  of  the  other  sorghums 
the  stems  and  leaves  remain  green  until  after  the  seed  is  ripe.  In 
addition  to  this  fact,  the  plants  stool  extensively  so  that  the  later 
suckers  will  be  quite  immature  even  when  the  main  stems  of  the  plant 
are  ripe.  On  the  other  hand,  if  the  crop  is  cut  before  heading,  the 
feeding  value  of  the  product  is  apt  to  be  quite  low  though  its  pala- 
tability  may  not  be  impaired. 

Method  of  Harvesting. — The  most  common  way  of  harvesting  the 
hay  crop  is  with  a  mower.  It  is  subsequently  handled  in  much  the 
same  manner  as  millets  and  other  coarse  grasses.  During  the  bright, 
warm  days  of  the  summer,  grass  cut  one  morning  will  usually  be  ready 
to  rake  into  windrows  or  bunches  the  next  day.  To  produce  a  bright 
hay  of  high  quality,  it  should  be  put  into  cocks  and  allowed  to  cure 
for  three  or  four  days  before  being  put  into  the  mow  or  stack.  While 
the  leaves  cure  quite  readily,  the  large  juicy  stems  retain  their  moist- 
ure somewhat  longer  so  that  hay  which  appears  to  be  well  cured  may 


212  UNIVERSITY  OF  CALIFORNIA EXPERIMENT  STATION 

still  contain  a  relatively  high  percentage  of  moisture.  At  Davis,  hay 
cut  in  July,  1915,  contained  from  25  to  35  per  cent  of  moisture  after 
curing  in  the  swath  and  windrows  for  three  days.  A  few  days  of 
additional  curing  in  the  cock,  however,  reduced  the  moisture  content 
to  20  per  cent  or  less. 

In  some  instances  the  grain  binder  has  been  used  for  harvesting 
the  hay  crop,  the  bundles  being  set  into  shocks  to  cure.  While  this 
method  facilitates  handling  somewhat,  it  is  not  likely  to  become  very 
popular  owing  to  the  difficulties  encountered  in  harvesting  a  heavy 
crop.  When  the  grass  has  been  planted  in  rows,  harvesting  may  be 
done  with  the  row  or  corn  binder.  As  neither  of  these  implements  is 
commonly  found  on  the  farms  in  California,  the  mower  will  doubtless 
be  the  most  popular  means  of  harvesting,  the  hay  then  being  handled 
as  any  other  hay  crop. 

Yield  of  Hay. — The  yields  of  hay  which  may  be  obtained  with 
Sudan  grass  will  vary  somewhat  with  the  conditions  of  the  soil,  the 
supply  of  moisture  and  the  other  factors  which  enhance  or  retard 
plant  growth,  though  the  first  two  factors  will  doubtless  be  of  the 
greatest  importance. 

During  the  three  years  in  which  Sudan  grass  has  been  grown  at 
Davis,  the  yields  of  cured  hay  have  varied  from  1.32  tons  to  9.59 
tons  per  acre,  on  the  individual  plots.  Considering  the  average  yields 
obtained  on  the  different  plots  for  dry  and  irrigated  land  each  season, 
the  results  have  been  as  follows : 

TABLE  IV 

Yield  of  Sudan  Grass  Hay 


1913 

Dry, 
tons  per  acre 

1.78 

Irrigated, 
tons  per  acre 

3.93 

1914 

5.26 

6.74 

1915 

5.86 

1916 

5.94 

The  results  here  given  include  the  average  of  all  dry  and  all  irri- 
gated plantings  regardless  of  the  time,  rate  or  method  of  seeding. 
Naturally,  plantings  made  rather  late,  producing  only  two  cuttings, 
will  not,  as  a  rule,  give  as  high  yields  as  earlier  plantings.  Further- 
more, it  is  quite  likely  that  the  application  of  more  water,  or  at  least 
applications  at  more  frequent  intervals,  would  have  increased  the 
yields  under  irrigation  materially.  In  these  experiments  only  one 
light  application  per  cutting  was  given,  which  may  not  have  been 
enough  for  the  maximum  growth. 


SUDAN  GRASS 


213 


FEEDING  VALUE  OF  SUDAN  GRASS  HAY 

The  feeding  value  of  a  product  depends  not  only  upon  its  com- 
position and  digestibility,  but  to  a  large  extent  upon  its  palatability 
to  the  animals  which  consume  it.  While  no  feeding  tests  have  as  yet 
been  conducted  with  Sudan  grass  hay,  observations  indicate  that  it 
is  relished  by  all  classes  of  hay-eating  animals,  nor  does  it  appear  to 
have  any  deleterious  effect  on  the  digestive  system.  Instances  have 
been  brought  to  our  attention  where  farm  stock  with  long  hours  of 
heavy  work  have  kept  in  good  condition  on  Sudan  grass  hay  without 
a  grain  ration. 


Fig.  4. — The  mower  is  well  adapted  to  harvesting  Sudan  grass  for  hay. 

The  palatability  of  the  product  is  doubtless  enhanced  by  the  juci- 
ness  and  sweetness  of  the  plants,  as  it  has  been  observed  that  even 
though  the  hay  is  rather  coarse,  but  little  waste  occurs  when  it  is  fed. 

Regarding  the  composition  of  the  hay,  claims  have  frequently  been 
made  that  it  compared  favorably  with  alfalfa  hay.  These  claims, 
however,  have  usually  been  advanced  by  parties  having  Sudan  grass 
seed  for  sale.  Analyses  made  of  the  hay  grown  at  the  University 
Farm  in  1915  in  comparison  with  some  of  the  more  common  hay  crops 
are  given  in  Table  V. 

The  data  in  this  table  clearly  show  that  Sudan  grass  compares  in 
composition  more  nearly  with  the  other  grass  hays  than  with  alfalfa. 
It  is  a  little  lower  in  protein  than  either  barley  hay  or  rye  grass  hay, 


Nitrogen 
free  extract 

Ash 

55.0 

7.2 

53.0 

4.9 

49.3 

9.2 

51.9 

5.0 

42.0 

8.8 

214  UNIVERSITY  OF   CALIFORNIA EXPERIMENT  STATION 

TABLE  V 

Average  Composition  of   Various  Hay  Crops — Water-Free  Basis* 

Crude 
Kind  of  hay  Protein  Pat  fiber 

Sudan   grass   6.9  3.0  27.9 

Barley  hay   10.3  2.8  29.0 

Eye   grass   10.5  3.5  27.5 

Timothy  6.8  2.9  33.4 

Alfalfa  16.8  2.3  30.1 

*  Analyses  supplied,  by  Professor  Woll. 

and  about  the  same  in  fat  and  crude  fiber.  Its  ash  content  is  consider- 
ably higher  than  that  of  barley  hay,  and  only  slightly  lower  than  that 
of  rye  grass  hay.  In  comparison  with  timothy  its  protein  and  fat 
content  are  approximately  the  same,  but  it  is  considerably  higher  in 
carbohydrates  and  ash.  The  hay  from  which  the  above  analyses  were 
made  was  cut  when  in  full  bloom,  which  is  the  usual  time  recom- 
mended for  harvesting  crops  of  this  character,  though  it  may  not 
necessarily  give  a  product  of  the  highest  nutritive  value. 

When  the  nutritive  value  per  unit  of  area  is  considered,  Sudan 
grass  is  superior  to  any  of  the  other  grain  hays  because  of  its  higher 
yield.  The  average  yield  of  Sudan  grass  hay  from  all  non-irrigated 
tests  during  the  first  three  years  has  been  8640  pounds  per  acre. 
Under  similar  conditions  4000  pounds  per  acre  is  considered  a  good 
yield  for  either  barley,  rye  grass  or  timothy  hay. 

In  Table  VI  is  shown  the  feeding  value  per  acre  of  the  grass  hays 
given  in  the  previous  table,  based  on  composition. 

TABLE  VI 

Yield  of  Constituents  in  Pounds  per  Acre  from  Grass  Hays 

Yield 
Kind  of  per  Dry  Crude         Nitrogen 

hay  acre  matter        Protein  Fat  fiber        free  extract       Ash 

Sudan  grass  8,640  6,367.7  439.4  191.0  1,794.6  3,485.2  457.5 

Barley  hay  4,000  3,400.0  350.2  95.2  996.0  1,792.0  166.6 

Eye  grass  4,000  3,520.0  369.6  123.2  968.0  1,735.5  323.8 

Timothy    4,000  3,316.0  225.5  96.2  1,107.5  1,721.0  165.8 

It  will  be  noted  that  the  acre  yield  of  protein  in  the  Sudan  grass 
is  about  twice  as  great  as  that  of  timothy  hay,  and  at  least  a  fourth 
more  than  rye  grass  or  barley  hay.  In  the  case  of  fat  and  ash  the 
acre  yield  of  Sudan  grass  is  more  than  twice  as  great  as  for  either 
barley  or  timothy  and  more  than  a  third  greater  than  rye  grass, 
while  its  yield  of  carbohydrates  is  double  that  of  the  other  grasses. 
While  the  value  of  Sudan  grass  hay,  per  unit  of  weight,  is  no  greater 
than  that  of  the  other  grass  hays,  the  larger  yields  per  acre  and  the 


SUDAN  GRASS  215 

fact  that  it  can  be  grown  under  conditions  wholly  unsuited  to  the 
other  types  will  doubtless  make  it  of  inestimable  value  to  the  stock 
growers  of  the  state. 

SUDAN  GRASS  PASTURE 

As  yet  but  little  definite  information  is  available  as  to  the  value 
of  Sudan  grass  for  pasture,  though  from  the  character  of  the  plant 
it  would  seem  to  lack  some  of  the  necessary  properties  of  a  good 
pasture  crop.  In  the  first  place  being  an  annual,  considerable  time 
would  be  required  for  the  root  system  to  develop  sufficiently  so  that 
the  plant  would  not  be  pulled  out  by  grazing  animals.  Again,  since 
the  soil  in  which  the  seed  is  planted  is  naturally  quite  soft,  the  young 
plants  would  probably  be  severely  injured  if  pastured  too  early.  If 
the  plants  were  allowed  to  attain  some  size  before  the  stock  is  turned 
in  but  little  injury  would  be  likely  to  result.  Another  possible 
objection  to  Sudan  grass  as  a  pasture  plant  is  that  being  a  sorghum, 
it  may,  if  subjected  to  extreme  drouth,  to  too  heavy  grazing,  or  other 
unfavorable  conditions,  develop  prussic  acid  (hydrocyanic),  which  is 
quickly  fatal  to  stock. 

The  fact  that  the  grass  will  maintain  rather  rapid  growth  through- 
out the  drier  portion  of  the  year,  however,  is  strongly  in  its  favor. 
This  ability  is  possessed  by  but  few  plants  which  could  be  used  for 
pasture  purposes.  The  danger  from  poisoning  by  members  of  the 
sorghum  family  has,  on  the  whole,  doubtless  been  over-estimated,  as 
the  death  rate  among  live  stock  from  this  source  is^very  low  as  com- 
pared with  other  causes. 

In  order  to  secure  some  information  on  the  value  of  Sudan  grass 
as  a  pasture  crop,  a  pasturing  experiment  was  begun  in  1916  in  co- 
operation with  the  Division  of  Animal  Industry.  While  the  results 
obtained  were  not  wholly  satisfactory,  the  ability  of  the  crop  to  with- 
stand rather  heavy  pasturing  after  the  plants  were  well-established 
was  amply  demonstrated. 

A  two-acre  field  of  silt  loam  was  chosen  for  the  experiment.  Be- 
cause of  the  dry  spring  it  was  necessary  to  irrigate  the  land  before 
seeding.  As  soon  as  the  soil  was  dry  enough  to  work  properly  the 
seed  bed  was  prepared  and  the  crop  seeded  at  the  rate  of  twenty 
pounds  per  acre  on  June  17.  The  seed  germinated  quickly  and  a 
good  stand  was  obtained  over  practically  the  whole  tract.  Since  it 
was  feared  that  the  plants  would  be  pulled  up  or  otherwise  injured 
if  the  stock  was  turned  on  while  the  plants  were  small,  pasturing 
was  not  begun  until  July  24,  at  which  time  the  plants  had  attained 
a  height  of  about  two  feet.    On  this  date  thirtv-five  lambs  were  turned 


216  UNIVERSITY  OF  CALIFORNIA EXPERIMENT  STATION 

into  the  field,  and  while  they  seemed  to  relish  the  feed  highly,  they 
made  practically  no  reduction  in  the  growth.  Three  days  later  eleven 
ewes  were  added  to  the  flock,  but  even  this  heavy  pasturing  did  not 
affect  the  growth  of  the  crop.  The  Sudan  grass  headed  about  the 
first  of  August  and  on  the  3rd  the  sheep  were  removed  and  the  crop 
cut  for  hay,  4.65  tons  of  cured  hay  being  removed  from  the  two  acres. 
Two  weeks  were  allowed  after  cutting  for  the  plants  to  recuperate 
before  being  again  pastured.  From  this  time  until  September  26  the 
field  was  pastured  intermittently ;  on  the  latter  date  fifteen  sheep  were 
again  put  upon  the  field  where  they  remained  until  October  29,  a  week 
after  the  growth  was  killed  by  frost.  All  the  sheep  made  gains  of 
about  one-third  of  a  pound  per  day  throughout  the  period  they  were 
on  pasture,  and  at  no  time  was  any  injurious  effect  noted.  Had  the 
field  been  seeded  earlier  and  had  the  proper  stage  of  growth,  as  well 
as  the  carrying  capacity  of  the  field  been  better  understood,  a  much 
longer  period  of  pasturing  would  doubtless  have  been  obtained. 

Many  reports  have  been  obtained  praising  Sudan  grass  as  a  sum- 
mer pasture  for  all  classes  of  livestock,  but  the  only  exact  data  that 
have  come  to  the  writers'  attention  were  submitted  by  Mr.  F.  F.  Lyons, 
while  Farm  Adviser  of  San  Joaquin  County,  citing  the  experience  of 
a  farmer  in  that  section  in  1915.  The  field  in  question  was  ten  acres 
in  size,  the  crop  being  planted  in  rows  three  feet  apart,  primarily  for 
seed  production  purposes.  The  seed  crop  was  cut  the  second  week 
in  July,  yielding  six  hundred  pounds  of  seed  per  acre.  As  soon  as 
the  new  growth  started,  seven  cows  and  five  horses  were  turned  in  and 
maintained  continually  until  the  crop  was  killed  by  frost  in  Novem- 
ber. The  horses  received  some  hay  in  addition  to  the  pasture,  but 
the  cows  received  no  other  feed  throughout  the  whole  period.  These 
results  are  indeed  remarkable  considering  the  manner  in  which  the 
crop  had  been  planted.  If  they  may  be  taken  as  an  indication  of 
what  can  be  expected  of  the  plant  for  pasture,  the  future  of  the  crop 
for  this  purpose  is  certainly  bright,  since  in  this  instance  at  least, 
it  equalled  in  carrying  capacity  a  good  stand  of  alfalfa. 

SEED  PKODUCTION 

Up  to  the  present  time  Sudan  grass  has  been  grown  primarily  as 
a  seed  crop,  owing  largely  to  the  high  price  which  this  produce  com- 
manded. While  these  high  prices  can  not  continue,  there  will  always 
be  a  considerable  demand  for  seed,  since  the  crop  is  an  annual  and 
must  be  seeded  every  year.  The  production  of  seed,  therefore,  will 
doubtless  continue  to  be  a  profitable  industry,  especially  in  those 
sections  where  a  good  quality  of  clean  seed  can  be  grown. 


SUDAN  GRASS 


217 


%  ** 


•%>. 


»" 


Fig.  5. — In  experimental  plantings   Sudan  grass  is  tall  and  vigorous  in   growth. 

When  in  bloom  it  is  ready  to  harvest. 


218  UNIVERSITY  OF  CALIFORNIA EXPERIMENT  STATION 

The  seed  habits  of  Sudan  grass  are  excellent.  It  is  produced  in 
large  open  panicles  ten  to  fourteen  inches  in  length,  borne  fairly 
high,  upon  erect  stalks  making  the  harvesting  of  the  crop  relatively 
easy.  The  seed  is  retained  quite  well  so  that  under  most  conditions, 
but  little  loss  from  shattering  will  result.  If,  however,  the  crop  is 
subjected  to  strong  winds,  when  the  seed  is  mature,  a  considerable 
portion  of  it  may  be  lost  by  shattering. 

The  first  crop  of  seed  requires  from  ninety-five  to  one  hundred 
days  to  mature  under  normal  conditions.  After  cutting,  the  plants 
recover  very  quickly  so  that  under  favorable  conditions  when  the 
growing  season  is  of  sufficient  length  a  second  crop  of  seed  may  be 
produced.  This  second  crop,  however,  usually  requires  from  one 
hundred  and  ten  to  one  hundred  and  twenty  days  to  mature,  so  there 
is  always  the  danger  of  its  being  injured  by  frost  before  it  is  ripe. 
Furthermore,  neither  the  yield  nor  the  quality  of  the  seed  from  the 
second  cutting  will  be  as  good  as  from  the  first. 

In  most  cases  it  will  doubtless  be  more  economical  to  utilize  the 
growth  after  the  seed  crop  either  for  hay  or  for  pasture,  or  else 
to  harvest  the  first  crop  of  the  season  for  hay,  allowing  the  second 
to  mature  seed.  In  this  latter  case  a  seed  crop  could  be  matured  in 
most  sections  of  the  state  without  the  danger  of  injury  by  frost. 

In  growing  a  seed  crop,  however,  care  should  be  taken  to  see  that 
it  is  grown  on  land  that  is  absolutely  free  from  Johnson  grass,  as  the 
seed  of  these  two  plants  are  so  nearly  alike  as  to  be  distinguished  only 
with  great  difficulty.  In  producing  seed,  farmers  should  aim  to  secure 
their  supply  from  sections  free  from  Johnson  grass  in  order  to  avoid 
the  danger  of  introducing  this  pest.  In  sections  where  Johnson  grass 
is  not  present,  it  will  probably  be  advisable  for  the  farmer  to  grow 
his  own  seed,  since  ordinarily  only  a  small  area  will  be  required  to 
produce  the  desired  amount.  In  sections  favorable  for  the  production 
of  seed,  good  returns  may  be  obtained  from  the  seed  crop  even  though 
the  price  drops  as  low  as  five  or  six  cents  as  at  present  indicated. 

Preparation  of  Soil. — As  yet  but  little  definite  information  is 
available  as  to  the  best  means  of  handling  the  seed  crop.  The  experi- 
ments conducted  thus  far  have  referred  primarily  to  the  method  of 
seeding  for  maximum  seed  production  and  not  to  the  other  cultural 
practices.  In  the  preparation  of  the  seed  bed,  however,  the  same 
general  cultural  methods  should  be  followed  as  in  the  production  of 
a  forage  crop.  It  should  be  mellow  and  well  prepared  in  order  to 
secure  a  uniform  stand  of  healthy  plants. 

Time  of  Seeding.— Early  planting  or  as  soon  as  the  soil  is  suf- 
ficiently warm  to  maintain  normal  growth  will  in  most  cases  be  pro- 


SUDAN  GRASS  219 

cluctive  of  the  best  results.  At  this  season  of  the  year  the  supply  of 
moisture  is  abundant  and  the  plants  will  ordinarily  make  a  better 
growth  than  if  seeded  later.  On  the  other  hand,  if  the  land  can  be 
irrigated,  later  seeding  may  be  practiced.  It  is  probably  never  advis- 
able, however,  to  plant  a  seed  crop  later  than  the  first  of  July,  since 
the  season  at  the  time  of  maturity  will  be  too  cool  for  the  best  devel- 
opment. 

Method  of  Seeding. — For  seed  production  Sudan  grass  may  be 
planted  either  in  close  drills  or  in  rows,  in  the  same  manner  as  de- 
scribed in  the  discussion  on  forage.  Owing  to  the  scarcity  of  seed 
during  the  past  two  or  three  years,  most  of  the  planting  for  seed 
production  has  been  in  cultivated  rows,  in  order  to  secure  as  large 
yields  as  possible,  by  forcing  the  plants  to  stool  extensively. 

Results  of  tests  conducted  at  Davis  during  the  season  1913  to  1915 
to  determine  the  value  of  different  methods  of  seeding  on  the  relative 
yield  of  hay  are  given  in  Table  VII. 

TABLE  VII 

Seed  Production,  Method  of  Seeding 

Yield  of  seed  per  acre,   pounds 
1913  1914  1915  1916 


_a .  . /V_ 


Method  Total  Total  One  One 

of  1st       2nd         for  1st         2nd  for  cut.  cut. 

seeding  cut.       cut.      season  cut.         cut.         season  only  only 

Dry— 

36-inch  rows  65  30  95  1,308     408.7     1,716.5         621.3         

18-inch  rows  50  60  110  1,340     490.5     1,830.5      1,013.7         

20  lbs.  drilled 150  35  185  1,303     457.8     1,765.8         964.6         

30  lbs.   drilled 120  30  150  

Irrigated — 

36-inch  rows  880  270  1,150             800     340        1,140              740 

18-inch  rows  400  180  580  1,540     490        2,030              940 

20  lbs.  drilled 280  30  310  1,240     530        1,760             1,760 

30  lbs.  drilled 680  30  710*  

*  Average  of  two  plots. 

The  results  given  in  this  table  for  the  seasons  1914  and  1915,  at 
least,  favor  planting  in  eigh teen-inch  rows.  In  1914,  however,  the  dif- 
ference when  no  irrigation  was  given  is  not  as  great  as  with  irrigation. 
In  1916,  on  the  other  hand,  when  the  crop  was  grown  with  irrigation 
much  the  best  results  were  obtained  from  the  close-drilled  plots.  The 
results  for  1913  were,  on  the  whole,  extremelv  variable.  One  would 
naturally  expect,  with  the  light  rainfall  which  obtained  that  season, 
that  the  thirty-six-inch  rows  would  have  given  the  highest  yield.  This 
expectation,  however,  was  upset  largely  by  the  poor  stand  obtained. 


220  UNIVERSITY  OF  CALIFORNIA EXPERIMENT  STATION 

Further  trials  under  similar  conditions  will  be  necessary  to  verify 
these  results. 

Bate  of  Seeding. — Unfortunately  no  definite  information  is  yet 
available  on  the  rate  of  seeding  for  the  maximum  seed  production. 
It  has  been  stated  that  if  a  light  rate  of  seeding  was  used,  the  strong 
tendencies  to  stool  profusely  would  cause  uneven  ripening  and  there 
fore,  a  poor,  immature  quality  of  seed.  This  same  objection  might  be 
raised  with  regard  to  growing  the  crop  in  cultivated  rows.  However, 
thus  far  the  results  obtained  at  Davis  have  not  borne  out  this  con- 
tention. When  seeded  in  close  drills  the  maximum  yields  will  prob- 
ably be  obtained  if  seeded  at  the  rate  of  from  fifteen  to  twenty  pounds 
per  acre  under  most  conditions.  When  seeded  in  cultivated  rows  the 
amount  of  seed  required  will  vary  with  the  distance  between  the  rows, 
usually  from  four  to  seven  pounds  per  acre. 

Harvesting  the  Seed  Crop. — The  seed  crop  should  be  cut  when  the 
majority  of  the  heads  on  the  main  portion  of  the  plant  are  ripe.  It 
is  seldom  wise  to  allow  it  to  stand  until  all  the  heads  on  the  later 
shoots  are  mature,  for  while  it  does  not  shatter  easily,  if  subjected  to 
the  hard  winds  prevalent  in  many  of  the  valleys  of  the  state,  a  con- 
siderable loss  is  bound  to  occur.  Furthermore,  the  plumpest  seed  is 
produced  on  the  main  heads  and  it  is  this  portion  that  would  be  lost 
if  shattering  occurred.  On  the  other  hand,  if  the  crop  is  cut  too  early, 
the  seed  will  be  light  and  chaffy,  with  the  result  that  a  considerable 
portion  of  it  will  be  screened  or  blown  out  in  the  threshing  and  clean- 
ing process.  For  harvesting  the  seed  crop  the  ordinary  grain  binder 
is  the  most  economical  as  well  as  the  most  efficient.  The  bundles  can 
then  be  set  into  shocks  to  cure,  where  they  should  remain  for  a  period 
of  from  ten  days  to  two  weeks.  If  desired,  the  bundles  may  be  stacked 
like  other  grain,  but  this  is  seldom  necessary  in  a  dry  climate  such  as 
prevails  in  California. 

Harvesting  may  also  be  done  with  a  mower,  cutting  and  handling 
the  crop  like  hay.  This  method,  however,  is  not  to  be  recommended 
as  a  considerable  quantity  of  seed  will  be  lost  in  the  process  of 
handling. 

Threshing. — Sudan  grass  may  be  threshed  with  the  ordinary  grain 
separator.  The  only  change  necessary  will  be  the  reduction  of  the 
air  blast  from  the  fan  to  prevent  the  seed  from  being  blown  over  with 
the  chaff.  If  the  cylinder  is  run  at  a  high  rate  of  speed,  or  if  several 
rows  of  concaves  are  used,  the  coverings  will  be  removed  from  a  large 
proportion  of  the  seed.  While  the  presence  or  absence  of  the  hulls 
does  not  appear  to  affect  the  germination  of  the  seed,  it  has  a  better 
appearance  if  the  glumes  are  retained.     For  this  reason  no  greater 


SUDAN  GRASS  221 

speed  of  the  cylinder  or  no  more  concaves  should  be  used  than  will  be 
necessary  to  completely  remove  the  seed  from  the  heads. 

Cleaning. — Even  though  most  of  the  chaff  and  foreign  material 
will  be  removed  in  threshing,  it  will  usually  be  necessary  to  reclean 
the  seed  in  order  to  secure  a  high-grade  product.  Any  ordinary  fan- 
ning mill  fitted  with  proper  screens  will  clean  Sudan  grass  seed, 
though  a  machine  possessing  a  vertical  air  blast  will  be  found  to  be 
the  most  efficient  for  the  removal  of  the  chaff  and  light  immature 
seed  which  can  not  be  removed  by  the  screen. 

Yield  of  Seed. — The  yield  of  seed  will  be  quite  variable,  according 
to  the  character  of  the  soil,  the  supply  of  moisture  and  the  general 
seasonal  condition  for  growth.  During  the  past  three  years,  the  yields 
of  seed  at  Davis  have  ranged  from  ninety-five  pounds  per  acre  to  two 
thousand  and  thirty  pounds  per  acre.  The  average  yields  for  the 
four  years  are  as  follows : 

Year                                                            Dry  Irrigated 

1913 135.0  687.5 

1914 1,770.9  1,643.0 

1915 866.5  

1916 1,146.6 

From  these  results  it  will  be  noted  that  there  was  a  very  wide 
difference  in  seed  production  in  different  seasons.  The  extremely  low 
yield  in  1913  was  due  to  the  combined  effect  of  extreme  drouth  and  a 
poor  stand.  The  conditions  in  1914,  1915,  and  1916,  however,  were 
excellent  for  seed  production,  though  in  1914  two  cuttings  of  seed 
were  obtained  while  in  1915  and  1916  only  one  seed  crop  reached 
maturity,  which  accounts  for  the  difference  in  these  two  seasons. 
From  these  data  and  from  observations  made  under  field  conditions 
in  several  sections  of  the  state  it  is  indicated  that  when  but  one  seed 
crop  is  obtained,  1000  pounds  or  over  may  be  considered  an  excellent 
yield,  while  the  average  production  will  probably  range  from  600 
to  800  pounds  per  acre. 

ENEMIES 

Diseases. — As  yet  but  few  diseases  have  occurred  on  Sudan  grass 
with  sufficient  severity  to  greatly  injure  the  growth  of  the  plants. 
Probably  the  worst  and  most  prevalent  disease  is  the  sorghum  blight 
or  red  spot,  mentioned  by  Vinall  in  Farmers'  Bulletin  no.  605,  and 
described  as  follows :  ' '  This  disease  is  characterized  by  the  appearance 
of  distinct  reddish  spots  or  blotches  on  the  leaves,  these  spots  grad- 
ually spreading  until  the  leaves  turn  brown  and  die.     Its  effect  on 


222  UNIVERSITY  OF  CALIFORNIA EXPERIMENT  STATION 

the  plant  is  much  the  same  as  rust  and  like  rust,  is  most  destructive 
in  warm  humid  regions — but  it  seems  possible  to  overcome  this  weak- 
ness by  the  production  of  disease-resistant  strains. '  This  disease  has 
been  observed  upon  nearly  all  Sudan  grass  plantings  in  this  state, 
but  in  no  case  has  it  appeared  to  injure  the  growth  severely. 

Another  disease  to  which  Sudan  grass  is  subject  is  sorghum  smut. 
As  yet,  however,  no  reports  of  infection  of  this  character  have  been 
received,  nor  is  it  apt  to  become  prevalent  or  cause  much  damage  since 
the  grass  will  be  used  primarily  as  a  hay  crop. 

Insects. — Probably  the  worst  insect  enemy  of  Sudan  grass  in  Cali- 
fornia is  the  grasshopper.  While  no  severe  infestations  have  as  yet 
been  reported,  it  is  known  that  grasshoppers  feed  abundantly  on  the 
green  plants  and  may  cause  considerable  damage  during  periodic  out- 
breaks. Probably  the  best  means  of  controlling  this  pest  is  by  the 
distribution  of  poisoned  baits  around  the  edges  of  the  field  or  between 
the  rows.  While  the  grass  is  small,  the  hopper  dozer  may  also  be 
employed  with  success. 

Weeds. — Since  Sudan  grass  is  an  annual  and  must  be  seeded  every 
year  and  because  of  the  rapidity  and  vigor  with  which  it  grows,  weeds 
are  not  likely  to  be  a  serious  menace  to  the  crop.  Such  perennial 
weeds  as  Johnson  grass  and  morning  glory  may,  if  present,  reduce 
the  stand  and  stunt  the  growth  somewhat.  The  former  plant  is 
especially  objectionable  when  a  seed  crop  is  to  be  grown  since  the 
plant  itself  and  the  seed  can  be  distinguished  from  Sudan  grass  only 
with  great  difficulty.  For  this  reason,  a  seed  crop  of  Sudan  grass 
should  never  be  grown  where  Johnson  grass  is  known  to  be  present. 

Source  of .  Seed. — The  original  supply  first  distributed  by  the 
United  States  Department  of  Agriculture  contained  no  Johnson  grass 
seed.  Seed  growers  and  others  who  have  produced  their  supply  from 
this  original  source  and  have  grown  it  on  lands  free  from  Johnson 
grass  and  on  those  not  in  close  proximity  to  Johnson  grass,  should 
have  pure  seed.  Our  supply  at  the  University  Farm  at  Davis  was 
secured  and  multiplied  in  this  manner. 

Sudan  grass  seed  has  now  become  a  staple  seed  crop,  and  we  find 
it  quoted  in  the  farm  papers  along  with  timothy  and  other  well  known 
seeds. 

The  seed  has  been  grown  to  such  an  extent  in  states  in  which  John- 
son grass  is  known  to  flourish  and  produce  seed  that  there  is  every 
possibility  that  some  Johnson  grass  seed  has  crept  in.  It  is  very 
evident  therefore  that  the  above  questions  can  not  be  satisfactorily 
answered.  In  regard  to  the  probabilities  of  Sudan  grass  containing 
Johnson  grass  seed,  however,  we  may  be  able  to  throw  some  light. 


SUDAN  GRASS  223 

Johnson  grass  is  a  perennial  and  produces  strong  pernicious  under- 
ground stems  or  root  stocks,  commonly  en  Hod  roots,  each  part  of  which 
when  broken  up  in  pieces,  is  capable  of  producing  a  new  plant.  These 
may  descend  to  a  depth  of  four  or  five  feet  in  the  soil.  Under  ordi- 
nary conditions  of  exposure,  these  roots  are  killed  by  freezing  so  that 
in  those  states  where  the  soil  freezes  to  a  depth  of  several  feet,  John- 
son grass  is  not  likely  to  survive.  This  would  include,  in  a  general 
way,  all  the  states  north  of  Kansas  and  a  large  area  in  an  irregular 
line  where  low  winter  temperatures  prevail.  Even  in  the  states  of 
Iowa  and  Michigan,  the  rootstocks  have  been  known  to  survive  the 
winters  occasionally,  but  only  under  favorable  conditions  for  protec- 
tion from  cold.  According  to  Vinall,  Sudan  grass  seed  has  been  pro- 
duced in  Ohio,  Minnesota  and  eastern  South  Dakota.  Growers  of 
Sudan  grass  for  hay  in  states  with  cold  winters,  need  not  have  the 
same  fear  of  introducing  Johnson  grass,  since  if  any  seed  should 
be  present  the  plants  from  these  would  most  likely  be  killed  during 
the  first  winter. 

It  has  been  stated  that  Sudan  grass  can  be  readily  distinguished 
from  Johnson  grass  by  its  larger  size  and  different  color.  Looking 
at  either  of  them  in  bulk  Sudan  grass  is  generally  plump  and  John- 
son grass  seed  slender,  but  this  can  not  be  relied  upon  as  individuals 
from  a  single  plant  of  Sudan  grass  will  vary  greatly  in  this  respect, 
due  to  the  different  stages  of  maturity  of  the  seed  and  the  cultural 
treatment  of  the  plant.  Again,  Sudan  grass  is  supposed  to  have  light- 
colored  seed,  while  Johnson  grass  is  dark-colored.  But  there  are  good 
strains  of  Sudan  grass  that  are  quite  dark  in  color,  as  well  as  light- 
colored  Johnson  grass  seeds,  so  that  color  can  not  be  relied  upon  in 
determining  the  purity  of  Sudan  grass. 

DISTINCTION  BETWEEN  SUDAN  GEASS  AND  JOHNSON  GEASS  SEED 

F.  H.  Hillman  of  the  Seed  Laboratory,  United  States  Department 
of  Agriculture,  has  recently  discovered  a  method  by  which  the  dreaded 
Johnson  grass  can  be  distinguished  from  Sudan  grass.  We  quote 
the  following  from  the  Weekly  News  Letter,  U.  S.  D.  A.,  vol.  Ill,  no. 
36,  April  12,  1916 : 

Careful  study  of  the  seeds  of  these  crops,  which,  though  closely  related  and 
quite  similar  in  appearance,  differ  greatly  in  their  agricultural  value,  has  re- 
sulted in  the  development  of  a  method  by  which  they  can  be  distinguished  through 
a  careful  and  thorough  examination  with  the  aid  of  an  ordinary  magnifying  glass 
which  enlarges  objects  to  the  extent  of  six  or  eight  diameters.  A  detailed  tech- 
nical description  of  the  method  has  been  prepared  and  will  be  published  in  the 
near  future   by  the   department,   but  in   view   of   the  widespread   interest  in   the 


224  UNIVERSITY  OF   CALIFORNIA EXPERIMENT  STATION 

subject  at  this  season  of  the  year,  when  plantings  of  Sudan  grass  will  soon  be 
made,  the  following  nontechnical  description  is  published. 

Seeds  of  Johnson  grass  are  noticeably  smaller  than  those  of  Sudan  grass. 
When  the  two  are  mixed,  seeds  evidently  smaller  than  others  may  be  suspected 
to  be  Johnson  grass. 

In  nearly  all  samples  part  of  the  seed  is  unhulled  and  part  hulled.  This  is 
true  of  seed  of  both  Johnson  grass  and  Sudan  grass.  The  smaller  size  of  the 
Johnson  grass  seed  is  evident  in  both  the  unhulled  and  hulled  seeds. 

On  closer  examination  under  the  magnifier,  most  of  the  unhulled  seeds  of 
Sudan  grass  are  seen  to  have  a  short  stem.  Besides  this,  the  two  slender  append- 
ages lying  on  one  face  of  the  seeds  are  broken  at  the  end.  Most  of  the  unhulled 
seeds  of  Johnson  grass  have  no  stem,  but  a  smooth  scar  instead.  The  two 
appendages  are  mostly  expanded  and  cup-shaped  at  the  end.  The  stem  and  the 
broken  appendages  in  Sudan  grass  seed  and  the  smooth  scar  and  entire  expanded 
appendages  in  Johnson  grass  seed  result  from  the  fact  that  nature  has  made 
no  special  provision  for  the  fall  of  the  seed  in  Sudan  grass,  while  in  Johnson 
grass  provision  is  made  for  the  seed  to  separate  from  the  plant  at  the  junction 
of  the  seed  with  its  stems  cleaving  a  clean-cut  scar.  At  this  point  a  distinct 
line  across  the  stem  marks  the  point  of  separation.  Exceptions  to  the  general 
rule  stated  occur  in  both  kinds  of  seeds.  Some  of  the  Sudan  grass  seeds  have 
no  stem,  but  the  appendages  are  rarely  entire  and  expanded  at  the  end.  Some 
Johnson  grass  seeds  have  a  stem  because  of  the  weaker  stem  having  broken  more 
readily  below  its  junction  with  the  seed  than  at  this  junction.  The  appendages 
are  rarely  broken,  and  narrow  at  the  end.  Johnson  grass  seeds  bearing  a  stem 
usually  can  be  recognized  by  the  distinct  division  line  across  the  stem  at  its 
junction  with  the  seed. 

Some  of  the  seeds  of  both  Sudan  and  Johnson  grass  have  a  longer  stem 
which  is  a  part  of  the  branch  bearing  the  seed  cluster. 

Lastly,  the  free  grains  or  hulled  seeds  of  Johnson  grass  are  smaller  and  darker 
colored  than  those  of  Sudan  grass,  and  are  usually  oval  in  form,  while  those  of 
Sudan  grass  are  elliptical. 

The  Branch  Seed  Laboratory  of  the  United  States  Department  of 
Agriculture,  at  the  College  of  Agriculture,  Berkeley,  is  now  prepared 
to  report  on  the  presence  of  impurities  in  Sudan  grass  seed,  including 
Johnson  grass. 


